This invention relates to an extensible multilayer laminate web, and more particularly to a laminate web wherein at least a elastic layer is extensible and apertured. In some embodiments the entire multilayer laminate web is extensible, elastic, and apertured.
Laminate webs formed by the joining of discrete webs in a layered relationship are well known in the art. For example, laminate nonwoven webs are often utilized in disposable absorbent articles such as diapers and adult incontinence products. Such laminated webs can be used as a topsheet, backsheet, or side panels. One example of a laminate web is a film/nonwoven laminate useful as a backsheet of a disposable diaper. Nonwoven/nonwoven laminates are also utilized to provide additional bulk or softness to a web component. Likewise, film/film laminate webs can provide benefits by combining the characteristics of various films in a layered relationship. Laminate webs can also be called composite webs.
Often laminate webs are intended to combine properties of the constituent layers to achieve synergistic benefits. For example, elastic materials can be combined with nonwoven webs to form elastically extensible nonwoven webs. Such materials can exhibit a plurality of gathers, or rugosities, when in a relaxed state. Elastic composite webs are useful as elastic waist portions, or stretch ear portions of disposable absorbent articles.
For many applications of laminate webs, it is beneficial to have apertures therethrough. Apertures add texture, which contributes to utility as well as aesthetics. For example, as a cleaning wipe, a laminate with apertures can capture and hold dirt better than a wipe without apertures.
A beneficial method of aperturing a nonwoven web, including laminates of nonwoven webs is disclosed in EP-A-852,483, issued to Benson et al. Disclosed is a laminate material having, for example, at least one layer of a spunbonded web joined to at least one layer of a meltblown web, a bonded carded web, or other suitable material. Such apertured webs are useful as the topsheet in a disposable absorbent article. However, this disclosure does not teach laminating webs comprising elastomeric materials to make an elastically extensible apertured web.
A perforated multilayer elastic coversheet comprising an intermediate elastic layer between upper and lower nonwoven layers is disclosed in EP-A-784,461 issued to Palumbo. The upper and lower layers are connected to the intermediate layer only around the perimeters of the perforations. While providing an apertured, elastic laminate, it is not apparent that the method disclosed could produce elastic laminates economically. It is also not apparent that the elastic laminate would be elastically extensible in more than one direction.
Accordingly, it would be desirable to have an elastically extensible apertured nonwoven web, the apertured web being characterized by a plurality of openings, or perforations, in the web, and being elastically extensible in at least two directions.
Further, it would be desirable to have an economically attractive method for making an elastically extensible apertured nonwoven web.
An elastic laminate web is disclosed. The elastic laminate web can be non-apertured or apertured, and comprises a first web, and a second web joined to the first web in a face to face relationship at a plurality of discrete bond sites having an aspect ratio of at least 2. The first and second webs form an interior region therebetween. An elastic material is disposed between the first and second webs. The elastic material is apertured in regions coincident the bond sites, such that the first and second webs are joined through the apertures. The laminate so produced can be stretched in a predetermined direction, such as by incremental stretching, to produce an apertured elastic laminate.
One method for forming the elastic laminate web of the present invention comprising the steps of:
(a) providing first and second web materials comprising thermoplastic material;
(b) providing at least one third elastomeric web material;
(c) providing a thermal point bonder having a plurality of protuberances;
(d) guiding the third elastomeric web material in a stretched condition between the first and second web materials in a face-to-face layered relationship to the thermal point bonder;
(e) displacing the third elastomeric web material with the protuberances at discrete, spaced apart locations to form apertures in the third material; and
(f) thermally point bonding the first and second outer web materials to form bond sites at discrete, spaced apart locations coincident with the protuberances, thereby forming a bonded laminate.
To make an apertured elastic web, the method comprises the additional step of:
(g) stretching the bonded laminate to form apertures in the elastomeric laminate web.
(h)